ASTM B619 nickel alloy c267 welded pipes

ASTM B619 is a specification standard that covers welded nickel and nickel-based alloy pipes suitable for general corrosion-resistant and high-temperature applications. Among these, Nickel Alloy C276 (UNS N10276) is a widely used grade due to its exceptional resistance to harsh environments, including oxidizing and reducing agents.

Key Features of Nickel Alloy C276 Welded Pipes

1. Material Composition

Nickel (Ni): Predominantly nickel-based, typically >57%.

Molybdenum (Mo): Around 15–17%, providing excellent pitting and crevice corrosion resistance.

Chromium (Cr): 14.5–16.5%, enhancing oxidation resistance.

Iron (Fe): 4–7%.

Tungsten (W): 3–4.5%, contributing to corrosion resistance in severe environments.

Carbon (C): Low, ≤0.01%, to prevent carbide precipitation and maintain weldability.

2. Mechanical Properties

Tensile Strength (min): 100 ksi (690 MPa).

Yield Strength (0.2% offset, min): 41 ksi (283 MPa).

Elongation (min): 40%.

3. Corrosion Resistance

Nickel Alloy C276 is particularly resistant to:

Strong oxidizing and reducing agents.

Acidic environments, including hydrochloric, sulfuric, and phosphoric acids.

Chloride-induced stress corrosion cracking and localized attacks like pitting and crevice corrosion.

Manufacturing Process of Nickel Alloy C276 Welded Pipes

1. Welding Process

Pipes are produced by longitudinal welding using methods such as:

TIG (Tungsten Inert Gas) Welding.

Plasma Arc Welding.

Weld seams are heat-treated and tested to ensure corrosion resistance and mechanical integrity.

2. Heat Treatment

Solution annealing is performed at 2050°F (1120°C) followed by rapid quenching to maintain the alloy’s microstructure.

3. Surface Treatment

Descaling and pickling are often used to enhance the pipe’s surface quality and remove oxidation.

4. Testing Standards

Non-Destructive Testing (NDT): Radiographic or ultrasonic inspection to verify weld integrity.

Hydrostatic Testing: Ensures pressure resistance.

Dimensional Checks: Per ASTM B619 tolerances.

Applications of ASTM B619 Nickel Alloy C276 Welded Pipes

1. Chemical Processing

Used in acid production and handling equipment due to excellent corrosion resistance.

2. Pollution Control

Suitable for scrubbers, dampers, and ducting in flue gas desulfurization (FGD) systems.

3. Marine Industry

Resistant to seawater and brine, making it ideal for heat exchangers and piping systems.

4. Power Generation

Handles aggressive conditions in power plants, including geothermal and nuclear facilities.

5. Pharmaceutical and Food Industries

Ensures purity and contamination-free processing due to its inert nature.

Advantages of Nickel Alloy C276 Welded Pipes

Exceptional Corrosion Resistance: Handles both oxidizing and reducing agents.

High-Temperature Stability: Performs well in environments up to 1900°F (1038°C).

Good Weldability: Low carbon content minimizes carbide precipitation during welding.

Longevity: Resistant to corrosion and mechanical wear, reducing maintenance costs.

ASTM B619 Standards for Welded Pipes